Cold hardiness & minimum temperature

Is Foxtail Orchid (Phalaenopsis stuartiana)cold hardy? Hardiness zone & min temp

Also called Stuart's Phalaenopsis.

More about foxtail orchid

About Foxtail Orchid

Phalaenopsis stuartiana · also called Stuart's Phalaenopsis · flowering

Phalaenopsis stuartiana is a Philippine species moth orchid grown for cascading, branched sprays of small white flowers whose lower halves and lips are speckled crimson-purple, plus handsome silver-mottled leaves. A warm, humid-forest epiphyte, it wants bright shade, a chunky bark mix, dry-back watering, and warmth to produce its generous, long-lasting displays.

Cold limit: USDA 11-12 (indoor in nearly all US homes) · RHS H1b (18-29°C)

Watch for — Bud drop: Low humidity or temperature swings while in bud. Raise humidity and keep conditions steady through budding.

What foxtail orchid's hardiness rating actually means

Foxtail Orchid is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Its RHS rating of H1b means: Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season. On the US scale that maps to USDA 11-12 (indoor in nearly all US homes) — the zones where it can be left outdoors year-round.

New to these scales? The USDA hardiness zone map explained covers how the zone numbers work, and you can find your own zone with the zone finder.

Minimum temperature — and what happens below it

Minimum survivable temperature is roughly about 10 °C (sustained cold below this is damaging). Foxtail Orchid has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for foxtail orchid as it gets too cold:

Below about about 10 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches.
A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover.
Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.

Can foxtail orchid go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 10 °C, in shade or dappled light, hardened off gradually.
Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C.
It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

Work back from your local frost dates with the frost-date calculator: the last spring frost and first autumn frost are what really decide when foxtail orchid can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Foxtail Orchid hardiness — frequently asked questions

Is foxtail orchid cold hardy?

Foxtail Orchid is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Indoor-only in almost every home. Foxtail Orchid can only live outside year-round in genuinely frost-free climates (roughly USDA 11-12 (indoor in nearly all US homes)); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature foxtail orchid can survive?

What hardiness zone is foxtail orchid?

Foxtail Orchid is rated USDA 11-12 (indoor in nearly all US homes) and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can foxtail orchid survive winter outside?

It can holiday outdoors in summer once nights are reliably above 10 °C, in shade or dappled light, hardened off gradually. Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C. It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

What happens to foxtail orchid below its minimum temperature?

Below about about 10 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches. A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover. Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.